Elleboys said:Homework Statement
A 240g ball and a 570g ball are connected by a 48.0-cm-long massless, rigid rod. The structure rotates about its center of mass at 110 rpm.
Homework Equations
KE = Iω^2
I = 1/12(mr^2)
The Attempt at a Solution
Since it has two masses and two different radius, I was not sure with what I should've done.
Curious3141 said:Where did your formula for the moment of inertia come from? That doesn't look like the moment of inertia of a solid sphere (ball) to me.
To do this problem, you need the radius of each ball. Are you given this?
The first step is to find the common centre of mass (COM) of the system. Do you know how to do that?
The next step is to calculate the moment of inertia of the system about that common COM. This can be done by summing up the moments of each ball. Remember to use the right formula and remember the parallel axis theorem.
The final step to find the rotational KE is trivial. But you should note that even your formula for rotational KE is wrong (missing a factor of 0.5).
Elleboys said:And by using KE = Iω^2, I can get the answer.
Am I on the right track?
Elleboys said:OHHHHH I see
And yes I put wrong formula for I.
So I believe that I need to find a center of mass, get moment of inertia of each particle about that COM, add them up and it will give me net moment of inertia.
And by using KE = Iω^2, I can get the answer.
Am I on the right track?
Rotational kinetic energy is the energy an object has due to its rotation around a fixed axis. It is a measure of how fast an object is rotating and how much mass is distributed away from its center of rotation.
Rotational kinetic energy is calculated using the formula E = 1/2 * I * ω^2, where E is the rotational kinetic energy, I is the moment of inertia, and ω is the angular velocity.
Rotational kinetic energy is the energy an object has due to its rotation, while linear kinetic energy is the energy an object has due to its linear motion. They are calculated using different formulas and have different units of measurement.
Rotational kinetic energy affects an object's motion by determining how fast it can rotate and how much force it can exert. The greater the rotational kinetic energy, the faster an object can rotate and the more force it can exert.
Some examples of rotational kinetic energy in everyday life include the spinning of a top, the rotation of a wind turbine, and the movement of wheels on a vehicle. Rotational kinetic energy is also important in sports such as figure skating, gymnastics, and discus throwing.